$\log_{15}225 = {?}$
Answer: If $\log_{b}x=y$ , then $b^y=x$ First, try to write $225$ , the number we are taking the logarithm of, as a power of $15$ , the base of the logarithm. $225$ can be expressed as $15\times15$ $225$ can be expressed as $15^2$ $15^2=225$, so $\log_{15}225=2$.